It's been a while since we covered this topic on this blog. There's not much new in the world of alternative sanitizers for swimming pools in recent years.

Chlorine is still King - and when one discusses alternative sanitizers, we normally refer to sanitizers that are alternative to chlorine (or bromine).

Although there are many 'helper' sanitizers, there are few products available that can fully replace the power and efficacy of chlorine, in response to bacteria, algae and pathogens. Very few that are complete 'alternatives' to using chlorine.

In fact, there is only one. One sanitizing system with enough power to keep pool water disinfected and sanitary.

Biguanides:A truly alternative pool sanitizer, biguanides are a hydrogen peroxide based sanitizer that is sold under various trade names like Baquacil, Soft Swim or Splashes.

Biguanide users love its ease of use. Just pour in a liquid sanitizer and algaecide every week or two. No chlorine smell, and for those with skin sensitive to chlorine, no irritation.

Biguanide users may have trouble with cloudy water, especially as pool water becomes warm. At 80 degrees or higher, the effectiveness of the sanitizer wanes, and more is needed, or other products are used to restore order. Biguanides can also be expensive, around 50% more expensive than using chlorine.

For these reasons, and perhaps also the advent of salt chlorination systems, biguanide use has decreased over the years. By some estimates, only 5% of swimming pools in the U.S. are using this alternative sanitizer.

Helper Sanitizers

Purifiers may be a better term to use, since according to the EPA, a sanitizer is a substance that kills or inactivates 99.9% of ALL microbials (bacteria, fungi, viruses) present in a sample. Chlorine and Biguanides are true sanitizers, or disinfectants.

Here's a list of other useful pool chemicals that help to purify the water, but because of their delivery systems, or other limitations, may not be safe to use as your only means of water treatment.

I call them 'Helper Sanitizers', because they reduce the workload of your main sanitizer. Think of them as supplements to a chlorine system.

Minerals:Specifically, Copper and Silver metals, which are helpful in controlling algae and bacteria, work by releasing positively charged ions into the water, which are attracted to negatively charged contaminants. Once the minerals are attached, they disrupt cellular processes and if enough of the ions pile on, the particle size can become large enough for your pool filter to remove them.

Active method devices, such as the Power Ionizer, or the Solar Clear Ionizer, use low voltage current (electrolysis) to attract the positively charged ions to a negatively charged plate. Rushing water sweeps away the released ions into the pool, where it soon finds an oppositely charged particle.

Passive method devices, such as Nature2, Pool Rx or Pool Frog, don't use electricity to discharge the mineral ions of copper or silver, but rather use an erosion chamber, where mineral pellets slowly dissolve, releasing their positively charged ions into the water that is moving through the chamber.

Minerals are excellent helper sanitizers, and can reduce your chlorine demand by up to 50%. They are not able to do the entire job of pool sanitation however, as they lack the ability to oxidize and remove dead contaminates.

Ozone:The world's most powerful sanitizer, I like to say - ozone is a molecule with 3 oxygen atoms. In the natural world, ozone is constantly be created and destroyed, gaining an atom and losing an atom, in a blink of an eye.

Delivery systems for creating and introducing the ozone molecule into pool water have improved dramatically in recent years, however, affordable ozone systems still struggle with the problem of getting the ozone molecule in touch with as many contaminants as possible, before the molecule gasses off the pool surface, or decays to ordinary diatomic oxygen.

Ozone can be produced, or created by using an ultraviolet lightbulb, housed in an air tight casing, or with a better method called Corona Discharge. Both of these methods produce ozone naturally in the upper atmosphere, from the sun's UV light and from the discharges from lightning storms. You know this as the ozone layer, it helps shield the earth from harmful solar radiation.

For inground pools, try the Del Eclipse line of pool ozonators. For aboveground pools, the Big Dipper was recently introduced by Del at a low price, to bring ozonation to more pool owners. For hot tubs or pools under 1000 gallons, the Del MCD-50 ozonator is another great ozonator. All Del ozonators are corona discharge units, with high output ozone.

Adding ozone to your pool or spa can, like a good helper sanitizer, reduce your sanitizer demand by up to 50%.

Alternative Purification, there is really only one complete system that replaces chlorine completely, that is Biguanides. But, you can use two other alternate purifying technologies to reduce reliance on chlorine, namely Minerals and Ozone. The benefit is in reducing the amount of chlorine you use, or that you need to produce with a salt chlorinator. Helper Sanitizers, I'm calling them.